Tape for semiconductor package and cutting method thereof

ABSTRACT

A tape for a semiconductor package is provided. The tape comprises a base comprising a plurality of cutting areas, leads formed in each of the cutting areas on the base, and narrow wires connected to the corresponding leads. The narrow wires in at least one of the cutting areas are offset from central lines of the corresponding leads.

The present application claims the priority of Chinese utility modelapplication No. 200720103481.4 filed with the Chinese IntellectualProperty Office on Feb. 6, 2007, which is incorporated herewith byreference.

BACKGROUND OF THE INVENTION

The present invention relates to a tape for semiconductor package and amethod of cutting thereof.

Tape automated bonding (TAB) was introduced as a replacement for aconventional wire bonding technology. TAB is now used for asemiconductor package such as a tape carrier package (TCP) and a chip onfilm (COF) in liquid crystal displays, watches, cameras, memory cards,calculators, personal computers and other electronic devices. TABprovides a high-density interconnect from IC chips to substrate,allowing full automation of the bonding of one end of the tape wiringpattern to the IC chips and the other end of the tape wiring pattern tothe substrate.

FIG. 5 is a schematic view showing a conventional (TAB/COF) tape with alead pattern on a base, in which a lead spacing A is 27 μm, a distance Bbetween the central lines of two adjacent leads 1 is 58 μm. A narrowwire 2 provided at the end of each lead 1 is uniformly formed at thecentral line of the correspondingly lead 1 so as to provide a centralnarrow wire pattern as show in FIG. 5. The production process shows thatsuch central narrow wire pattern is prone to result in some technicaldefects when cutting the narrow wires, such as reducing life of acutting tool and producing burrs at cut edges of the cutted narrow wiresand the like.

When the conventional TAB/COF tapes are sequentially cut with a cuttingtool, the cutting positions of the cutting tool for the narrow wires ofeach tape are constant in the continuous operations, and thereby thesepositions of the blade of the cutting tool are subject to repeatingwear. The life of the cutting tool is only about 100,000 times ofcutting. If the cutting tool cannot be replaced in time, the worncutting tool will generate burrs at the cut edges. When a burr is largerthan 15 μm in length, it may cause a short between two adjacent leads,resulting in two-bright line (two-line) defect.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide a tape for semiconductorpackage in view of the problems such as reduced life of a cutting tooland the two-line defects resulting from edge burrs.

In an embodiment, the invention provides a tape for semiconductorpackage comprising a base and leads and narrow wires connected tocorresponding leads on the base. The base comprises a plurality ofcutting areas. Leads and narrow wires are formed in each of the cuttingareas. The narrow wires in at least one of the cutting areas are offsetfrom central lines of the corresponding leads.

Preferably, the narrow wires in the at least one of the cutting areasmay be offset from central lines of the corresponding leads towards asame direction, and alternatively, the adjacent narrow wires in the atleast one of the cutting areas may be offset from central lines of thecorresponding leads towards opposite directions.

Preferably, an offset distance between a central line of a narrow wireand a central line of the corresponding lead is 11 μm˜15 μm, morepreferably 13 μm.

In another embodiment of the invention, there is provided a method forcutting a tape for semiconductor package. The tape comprises a basehaving plurality of cutting areas, and leads and narrow wires connectedto corresponding leads which are formed within each of the cutting areason the base. The narrow wires in at least one of the cutting areas areoffset from central lines of the corresponding leads.

Preferably, the narrow wires may be arranged differently in the twoadjacent cutting areas.

Preferably, all the narrow wires in one of the cutting areas may beoffset from central lines of the corresponding leads towards a samedirection, and alternatively, the adjacent narrow wires in one of thecutting area may be offset from central lines of the corresponding leadstowards opposite directions.

Preferably, an offset distance between a central line of a narrow wireand a central line of the corresponding lead is 11 μm˜15 μm, morepreferably 13 μm.

Preferably, the tape for semiconductor package may be a TAB/COF tape.

Further scope of applicability of the present invention will becomeapparent from the detailed description given hereinafter. However, itshould be understood that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications within the spirit and scope of the invention will becomeapparent to those skilled in the art from the following detaileddescription.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features, aspects and advantages of the presentinvention will become more apparent from the following detaileddescription of the exemplary embodiments when taken in conjunction withthe accompanying drawings, in which:

FIG. 1 is a schematic view of a left offset narrow wire patternaccording to an embodiment of the present invention;

FIG. 2 is a schematic view of a right offset narrow wire patternaccording to an embodiment of the present invention;

FIG. 3 and FIG. 4 are schematic views of left and right offset narrowwire patterns according to an embodiment of the present invention; and

FIG. 5 is a schematic view of a conventional TAB/COF tape.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

It should be understood that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications within the spirit and scope of the invention will becomeapparent to those skilled in the art from the following detaileddescription. For understanding easily, the same reference numbers willrefer to the same element in common.

Several kinds of offset narrow wire patterns of tapes for semiconductorpackage according to the embodiments of the present invention aredescribed with conjunction of the drawings by way of example. Suchexamples comprise a TAB/COF tape used in a liquid crystal display (LCD)device.

Example 1

FIG. 1 is a schematic view of a left offset narrow wire pattern of atape for semiconductor package according to an embodiment of the presentinvention. As shown in FIG. 1, the tape such as a TAB/COF tape comprisesa base 10, and leads 1 are uniformly arranged on the base 10 in a leadpattern. A narrow wire 2 is provided on the end of each lead 1 and isconnected with the end of the corresponding lead 1. All the narrow wires2 in a cutting area are offset from the central lines 11 of thecorresponding leads 1 towards a left direction so as to form a leftoffset narrow wire pattern. The offset distance C between a central line21 of a narrow wire 2 and a central line 11 of the corresponding lead 1is 11 μm˜15 μm, preferably 13 μm.

Example 2

FIG. 2 is a schematic view of a right offset narrow wire pattern of atape for semiconductor package according to an embodiment of the presentinvention. Different from the left narrow wire pattern as shown in FIG.1, all the narrow wires 2 provided at ends of the corresponding leads onthe base 10 are offset from the central lines 11 of the correspondingleads 1 towards a right direction so as to form a right offset narrowwire pattern in example 2. The offset distance C between a central line21 of a narrow wire and a central line 11 of the corresponding lead 1 is11 μm˜15 μm, preferably 13 μm.

Example 3

FIG. 3 and FIG. 4 are schematic views of left and right offset narrowwire patterns of tapes for semiconductor package according to anembodiment of the present invention. As shown in FIG. 3 and FIG. 4,leads 1 are uniformly provided on a base 10 of the tape. Two adjacentnarrow wires 2 in a cutting area are offset from the central lines 11 ofthe corresponding leads 1 towards opposite directions so as to form aleft and right offset narrow wire pattern.

With respect to same positions of the tape for semiconductor package,two adjacent leads 1 (e.g., two leads on the most left side) may havetwo different arrangement manner, that is, the two narrow wires 2 of theleads become closer to each other (as shown in FIG. 3) or far away fromeach other (as shown in FIG. 4) due to offsetting from the central lineof the corresponding lead 1 in the opposite directions. In the left andright offset narrow wire pattern, the offset distance C between acentral line of a narrow wire and a central line of the correspondinglead 1 is 11 μm˜15 μm, preferably 13 μm. When width “D” of the narrowwires 2 is 4 μm˜6 μm, the maximum distance E between two adjacent narrowwires 2 may be 76 μm˜78 μm, and in contrast, the distance B between twoadjacent narrow wires of the leads in the conventional tape is 43 μm.

A method of cutting a tape for semiconductor package, such as a TAB/COFtape, according to an embodiment of the present invention will bedescribed in connection with a left offset narrow wire pattern. In thecutting areas consecutively arranged on a base of a TAB/COF tape, theleft offset narrow wire pattern as shown in FIG. 1 is applied in an oddcutting area on the base, while the central narrow wire pattern in theconventional tape as shown in FIG. 5 is applied in an adjacent evencutting area on the base. During the cutting process, when the oddcutting area is cut, the cutting positions where the cutting tool cutsthe narrow wires is offset from the central lines of the correspondingleads 1 by 11 μm˜15 μm, and when the even cutting area is cut, thecutting positions are at the central lines of the corresponding leads 1.That is, the cutting positions for every one cutting area are differentand alternated, which makes the blade of the cutting tool more uniformlyworn and thus lengthen the life of the cutting tool. Correspondingly,occurrence of edge burrs is reduced and thereby two-line defects in aLCD device can be avoided.

In other embodiments of the present invention, different narrow wirepatterns are employed in an odd cutting areas and in an adjacent evencutting area, respectively. Therefore, any combination of a left offsetnarrow wire pattern, a right offset narrow wire pattern, a left andright offset narrow wire pattern (such as the above described twokinds), and a conventional central narrow wire pattern can be appliedfor two adjacent cutting areas, and can be used to alleviate the worn tothe cutting tool and thus reduce occurrence of edge burrs when cuttingwith a cutting tool. Also, there may be two adjacent cutting areas thathave the same the narrow wire patterns, but with respect to the all thecutting areas of the tape, the narrow wire patterns are not the same atall.

The experiment results show that after using the tape for semiconductorpackage and the method of cutting according to the embodiments of thepresent invention, the life of the cutting tool is lengthen by more than1 factor, for example from 100,000 times of cutting to 200,000 times ormore of cutting, and occurrence of edge burrs are reduced.Correspondingly, two-line defects due to occurrence of edge burrs areavoided along with reduced product cost.

It should be appreciated that the embodiments described above areintended to illustrate but not limit the present invention. Although thepresent invention has been described in detail herein in connection withthe preferred embodiments, it should be understood by those skilled inthe art that various modification and equivalents of the invention canbe made herein without departing from the spirit and scope of thepresent invention as defined in the appended claims.

1. A tape for a semiconductor package, comprising: a base comprising a plurality of cutting areas, which are consecutively arranged along the tape and adapted to be cut in consecutive processes, wherein each cutting area on the base comprises leads of uniform width, which are arranged parallel to each other, and narrow wires of uniform length and width, which are arranged parallel to each other, a width of the narrow wires is less than that of the leads, and the cutting positions in each cutting area are provided on the narrow wires, and wherein the narrow wires are directly connected to ends of the corresponding leads and offset from the central lines of the corresponding leads all in a same manner in at least one of the cutting areas, and a narrow wire pattern offset in one of the cutting areas differs from a narrow wire pattern offset of an adjacent cutting area.
 2. The tape according to claim 1, wherein an offset distance between a central line of a narrow wire and a central line of the corresponding lead is 11 μm˜15 μm.
 3. The tape according to claim 2, wherein the offset distance between the central line of the narrow wire and the central line of the corresponding lead is 13 μm.
 4. The tape according to claim 1, wherein the tape is a tape automated bonding (TAB)/chip on film (COF) tape.
 5. The tape according to claim 1, wherein the narrow wire pattern offsets of any two adjacent cutting areas are arranged differently.
 6. A method for cutting a tape for a semiconductor package, the tape comprising a base comprising a plurality of cutting areas, which are consecutively arranged along the tape, wherein each cutting area on the base comprises leads of uniform width, which are arranged parallel to each other, and narrow wires of uniform length and width, which are arranged parallel to each other, a width of the narrow wires is less than that of the leads, and the cutting positions in each cutting area are provided on the narrow wires, and wherein the narrow wires are directly connected to ends of the corresponding leads and offset from the central lines of the corresponding leads all in a same manner in at least one of the cutting areas, and a narrow wire pattern offset in one of the cutting areas differs from a narrow wire pattern offset of an adjacent cutting area; and wherein the cutting areas are consecutively arranged along the tape and cut consecutively.
 7. The method according to claim 6, wherein the narrow wire pattern offsets of any two adjacent cutting areas are arranged differently.
 8. The method according to claim 6, wherein an offset distance between a central line of a narrow wire and a central line of the corresponding lead is 11 μm˜15 μm.
 9. The method according to claim 8, wherein the offset distance between the central line of the narrow wire and the central line of the corresponding lead is 13 μm.
 10. The method according to claim 6, wherein the tape is a tape automated bonding (TAB)/chip on film (COF) tape.
 11. A tape for a semiconductor package, comprising: a base comprising a plurality of cutting areas, which are consecutively arranged along the tape and adapted to be cut in consecutive processes, wherein each cutting area on the base comprises leads of uniform width, which are arranged parallel to each other, and narrow wires of uniform length and width, which are directly connected to ends of the corresponding leads and arranged parallel to each other, a width of the narrow wires is less than that of the leads, and cutting positions in each cutting area are provided on the narrow wires, and wherein the narrow wires in at least one of the cutting areas are offset from central lines of the corresponding leads, and the adjacent narrow wires are arranged in pairs, which are same as each other, and in each pair the narrow wires are offset from the central lines of the corresponding leads towards opposite directions, and a narrow wire pattern offset in one of the cutting areas differs from another narrow wire pattern offset in another cutting area.
 12. The tape according to claim 11, wherein an offset distance between a central line of a narrow wire and a central line of the corresponding lead is 11 μm˜15 μm.
 13. The tape according to claim 11, wherein the tape is a tape automated bonding (TAB)/chip on film (COF) tape.
 14. The tape according to claim 11, wherein the narrow wire pattern offsets of any two adjacent cutting areas are arranged differently. 